Machine Type Communication (MTC) User Equipment (UE or Terminal), also known as Machine to Machine (M2M) user communication equipment, is the major application form of the Internet of Things. Several technologies suitable for Cellular Internet of Things (C-IOT) are disclosed in the 3rd Generation Partnership Project (3GPP) Technical Report TR45.820V200, among which a Narrowband Long-Term Evolution (NB-LTE) technology is the most remarkable. The system bandwidth of the system is 200 kHz, which is the same as the channel bandwidth of a Global System for Mobile Communication (GSM) system, and greatly facilitates the reuse of GSM spectrum by the NB-LTE system and reduces the mutual interference between adjacent GSM channels. The NB-LTE system has the same bandwidth and downlink subcarrier spacing as that of one Physical Resource Block (PRB) of a LTE system, which are respectively 180 kHz and 15 kHz.
As a substitution to a 3GPP Rel-6 rate matching algorithm, Rate Matching (RM) of a Circular Buffer (CB) provides a method that can easily generate a puncture pattern with excellent performances. Bits selected for transmission can be read from any point in the circular buffer. If the end of the circular buffer is reached, data can be read around the start position of the circular buffer until L bits are read completely. Different locations can be specified in the circular buffer as the start position for a Hybrid Automatic Repeat Request (HARQ) data packet to read during each transmission. The definition of a redundancy version determines multiple start positions for the HARQ data packet to read in the circular buffer. The value of the redundancy version determines the specific start position for the HARQ data packet to read in the circular buffer during this transmission. As shown in FIG. 1, in the 3GPP system, the HARQ processing procedure based on the circular buffer rate matching defines four circular Redundancy Versions (RV) (RV=0, 1, 2, 3). A long sub-packet of the L bits during each HARQ retransmission is composed of L bits clockwise selected from the start position defined by the redundancy versions.
Systems based on Orthogonal Frequency Division Multiplexing (OFDM) include an Orthogonal Frequency Division Multiple Access (OFDMA) system, a Single-carrier Frequency-Division Multiple Access (SC-FDMA) system, and the like.
As shown in FIG. 2, in an OFDM system, one Resource Block (RB) is a time-frequency two-dimensional cell composed of multiple OFDM symbol intervals consecutive in a time aspect and multiple subcarriers consecutive in a frequency aspect, i.e., the duration of one RB is one subframe, and multiple subcarriers are included in the frequency aspect. In FIG. 2, one column refers to one OFDM symbol, and one row refers to one subcarrier.
To enhance the coverage of a narrowband IoT system, it is necessary to repeatedly transmit coded information data for multiple times, so that the received signals can be enhanced.
In current coverage enhancement technologies, an entire transport block is repeated in general. However, it has been found by the inventor of the present application in the process of studying the coverage enhancement of the narrowband IoT system that one transport block tends to continuously occupy multiple subframes in a narrowband LTE communication system because the available bandwidth in the frequency domain is smaller. If the current repeating manner is employed, the time span is too long, which is disadvantageous for fast combining and decoding at a receiving end. At the same time, since a wireless channel is a time-varying channel, the longer the time span is, the greater the change of the wireless channel is, and meanwhile, the data combining performance is also reduced.
This section provides background information related to the present disclosure which is not necessarily prior art.